By definition, a static attribute or method is one that does not require an instance to be used.
This means that a static method, as in your example, can be run freely without the need for instantiation of an object. However, due to its strong connection to the class (since it is stated in its scope) this means that its use requires the mention is its origin, and therefore the class serves as a form of organization of functions of more general use.
Therefore, the creation of static methods (or attributes) is interesting when it is intended that they are of free use, but well identified by a context represented by the class.
Classical examples are the mathematical functions such as sine, cosine, square root, etc., or constants such as PI, E, etc. Many languages implement these functions statically in a specific class for mathematical elements, allowing doing, for example:
float valor = Math.sin(Math.PI);
The method for the calculation of sine (Math.sin
) is general because it calculates the sine value given only the radian angle received as parameter. Therefore, it does not require an object instance and it makes sense to be created in a static way. Its inclusion in the math class (Math
) together with other methods and attributes (such as Math.PI
) allows organizing these implementations in the same significant context (i.e., of mathematics) for the developer who uses them.
In your example, you can consider this aspect of generality of what you want to achieve with the implementation when deciding to create the method as static or not:
- If you just want to read the file and return the content in textual format, very likely a static method will suffice. Especially if there will be other features that will also have this character and make sense to be grouped in the same class.
- On the other hand, if this implementation can make use of previously processed states or information or can produce something that persists for future executions, it seems natural that an instance is needed to at least store this information and states.
P.S.: In fact, I think that any existing feature in a programming language can be used incorrectly to the point of becoming a "bad practice". This does not mean that the use of the resource is always inappropriate.
A good example of using
método
static is the standardSingleton
. This pattern has a constructorprivado
which is instantiated by the class static method itself and ensures that one and only one instance of a given object exists in the execution of the application.– Roger Barretto